the tests were taken, its ranking has dropped in all three subjects now placing 26th in math, 21st in science, and 17th in reading. >> we're running in place as other high-performing countries start to lap us. >> reporter: some of those ranking ahead of the united states are china, canada, germany, poland and latvia, even developing countries like vietnam. >> asian countries like korea, like japan, like taiwan, and now like vietnam which are doing extraordinarily well because they make it very clear to their students in high school just exactly how important education is. >> reporter: we saw that firsthand on a recent visit to shanghai. why do you want to study so much? >> because i want to have a better future. and do some contribution to our society. >> reporter: but some argue the low rankings reflect what they call america's emphasis on testing, the diverse population, and others cite poverty as a factor. america has a child poverty rate nearly double that of countries like canada and germany who out-perform the united states. today's results are a sobering reminder that for america, an e